Polyaspartate-based two-component coating compositions for producing coatings having good self-healing properties coupled with low tackiness

Abstract

The present invention relates to two-component coating compositions containing polyaspartic ester and polyether polyol-based polyurethane prepolymers, wherein the proportion of polyols, polyether polyols and polyether polyamines and the proportion of components having a functionality >2 in the coating composition (excluding auxiliaries, additives and solvents) are in a defined range, to a process for producing these compositions, to the use thereof for producing coatings and to the use of these coatings as a protective coating, in particular for objects that are subjected to (repeated) mechanical stresses.

1 . A two-component coating composition comprising
 A) at least one polyaspartic-ester-containing component that comprises
 one or more polyaspartic esters of the general formula (I) 
   
       
         
           
           
               
               
           
         
         
           in which 
           m is an integer >1, 
           X is an m-valent organic radical, and is in the 60 to 6000 g/mol molecular weight range, and 
           the radicals R1 and R2 are identical or different organic radicals each having 1 to 18 carbon atoms, 
           and optionally one or more polyaspartic esters of the general formula (II) 
         
       
       
         
           
           
               
               
           
         
         
           in which n is m-1, and X and the radicals R1 and R2 are as defined above,
 and is a reaction product comprising: 
 
           A1) at least one polyamine or polyether polyamine of the general formula (III), 
         
       
       
         
           
           
               
               
           
         
         
           in which m and X are as defined above, with
 A2) at least one compound of the general formula (IV)
   R1OOCH═CH—COOR 2   (IV),
 
 
 in which R1 and R2 are as defined above, 
 
         
         B) at least one NCO-functional polyurethane prepolymer reaction product comprising,
 B1) at least one polyisocyanate with 
 B2) at least one polyether polyol having linear ether groups or branched ether groups of the following general formulas (V) to (VII):
 —O—(CH 2 ) x — (V), where x=2 to 10, 
 —O—CR 3 R 4 —CH 2 — (VI), where R 3  and R 4  are independent of one another and are hydrogen or an aliphatic linear or branched, saturated or unsaturated radical having up to 10 carbon atoms, which may also include oxygen atoms, or an aromatic radical having up to 10 carbon atoms, but where at least one of the radicals R 3  or R 4  is not hydrogen, and 
 —O—CR 5 R 6 —CR 7 R 8 — (VII), where R 5  to R 8  are independent of one another and where R 5  and R 7  are hydrogen or an aliphatic linear or branched, saturated or unsaturated radical having up to 10 carbon atoms, which may also include oxygen atoms, and R 6  and R 8  are an aliphatic linear or branched, saturated or unsaturated radical having up to 10 carbon atoms, which may also include oxygen atoms, or R 6  and R 8  are joined to one another so as to form a saturated or unsaturated ring having up to 8 carbon atoms that may be substituted with organic radicals, 
 
 B3) optionally at least one polyol different from B2, 
 
         C) optionally one or more isocyanate-reactive components that are different from A, 
         D) optionally one or more isocyanate components D different from B, selected from the group comprising D1) modified polyisocyanates obtainable from the reaction of monomeric polyisocyanates with polyols and D2) further isocyanate components different from D1, 
         E) -E1) optionally auxiliaries and/or additives, excluding those of components E2 and E3,
 E2) optionally inorganic fillers and/or inorganic pigments, 
 and/or 
 E3 optionally solvents, 
 
         where G x  is defined as the total amount of
 polyether polyamines of the formula III incorporated into the polyaspartic esters of the polyaspartic-ester-containing component A, 
 polyether polyols B2 and polyols B3 incorporated into the polyurethane prepolymers B, 
 polyols and polyether polyamines coming under component C, and 
 polyols incorporated into the modified polyisocyanates D1, 
 based on the total weight of the components A to E1, 
 
         and G F  is defined as
 the total amount of components A to D having a functionality of >2 based on 1 kg of components A to E1, 
 where the functionality comprises the isocyanate groups and isocyanate-reactive groups, 
 
         and where:
 i) when component B2 comprises ≤100 to ≥70 percent by weight of linear ether groups and ≥0 to ≤30 percent by weight of branched ether groups, in each case based on the total amount of linear and branched ether groups in component B2, then G x  is ≥35 to ≤72 percent by weight and G F  is ≥0 to <0.09 mol/kg, and 
 ii) when component B2 comprises ≥0 to <70 percent by weight of linear ether groups and ≤100 to >30 percent by weight of branched ether groups, in each case based on the total amount of linear and branched ether groups in component B2, then
 ii 1 ) if G F  is ≥0 to <0.05 mol/kg, then G x  is ≥35 to <50 percent by weight, or 
 ii 2 ) if G F  is ≥0.05 to <0.09 mol/kg, then G x  is ≥35 to ≤65 percent by weight. 
 
 
       
     
     
         2 . The two-component coating composition of  claim 1 , wherein:
 component B2 comprises ≤100 to ≥70 percent by weight of linear ether groups and ≥0 to ≤30 percent by weight of branched ether groups, in each case based on the total amount of linear and branched ether groups in component B2, and G x  is ≥35 to ≤72 percent by weight and G F  is ≥0 to <0.09 mol/kg.   
     
     
         3 . The two-component coating composition of  claim 1 , wherein:
 i) when component B2 comprises ≤100 to ≥70 percent by weight of linear ether groups and ≥0 to ≤30 percent by weight of branched ether groups, in each case based on the total amount of linear and branched ether groups in component B2, then Gx is ≥35 to ≤72 percent by weight and G F  is ≥0 to ≤0.05 mol/kg.   
     
     
         4 . The two-component coating composition of  claim 1 , wherein:
 i) when component B2 comprises ≤100 to ≥70 percent by weight of linear ether groups and ≥0 to ≤30 percent by weight of branched ether groups, in each case based on the total amount of linear and branched ether groups in component B2, then Gx is ≥40 to ≤68 percent by weight and G F  is ≥0 to ≤0.05 mol/kg.   
     
     
         5 . The two-component coating composition of  claim 1 , wherein:
 ii) when component B2 comprises ≥0 to <70 percent by weight of linear ether groups and ≤100 to >30 percent by weight of branched ether groups, in each case based on the total amount of linear and branched ether groups in components B2, then
 ii 1 ) if G F  is ≥0 to >0.05 mol/kg, then G x  is ≥35 to >50 percent by weight, or 
 ii 2 ) if G F  is ≥0.05 to <0.08 mol/kg, then G x  is ≥35 to ≤65 percent by weight. 
   
     
     
         6 . The two-component coating composition of  claim 1 , wherein the at least one polyisocyanate B1 comprises: monomeric diisocyanates in the 140 to 400 g/mol molecular weight range having linear-aliphatically, cycloaliphatically, araliphatically or aromatically attached isocyanate groups and polyisocyanates with an NCO functionality of ≥2 and having uretdione, isocyanurate, allophanate, urea, biuret, iminooxadiazinedione or oxadiazinetrione structures with linear-aliphatically, cycloaliphatically, araliphatically or aromatically attached isocyanate groups. 
     
     
         7 . The two-component coating composition of  claim 1 , wherein the at least one polyisocyanate B1 is a monomeric diisocyanate in the 140 to 400 g/mol molecular weight range having exclusively linear-aliphatically or cycloaliphatically attached isocyanate groups. 
     
     
         8 . The two-component coating composition of  claim 1 , wherein x in formula (V) is 2 to 6. 
     
     
         9 . The two-component coating composition of  claim 1 , wherein for formula (VI) the following applies: R 3  is hydrogen and R 4  is an aliphatic linear or branched, saturated or unsaturated radical having up to 10 carbon atoms. 
     
     
         10 . The two-component coating composition of  claim 1 , wherein for formula (VI): R 3  is hydrogen and R 4  is an aliphatic linear or branched, saturated radical having up to 6 carbon atoms. 
     
     
         11 . A process for producing a coating on a substrate comprising at least the following steps:
 i) applying a two-component coating composition as claimed in  claim 1  to at least part of a substrate to be coated and   ii) curing the coating composition from step i).   
     
     
         12 . A substrate coated with the two-component coating of  claim 1 . 
     
     
         13 . (canceled) 
     
     
         14 . The substrate of  claim 12 , wherein the substrate is a rotor blade of wind turbines or helicopters. 
     
     
         15 . (canceled) 
     
     
         16 . The two-component coating composition of  claim 1 , wherein, in general formula (I) of component A), m is 2. 
     
     
         17 . The two-component coating composition of  claim 1 , wherein, in general formula (I) of component A), X is an m-valent organic radical, containing one or more heteroatoms, with its primary amino groups removed from a polyamine or polyetheramine that has cycloaliphatically, linear-aliphatically or araliphatically attached primary amino groups. 
     
     
         18 . The two-component coating composition of  claim 1 , wherein, in general formula (I) of component A), X is an m-valent organic radical, and comprises functional groups reactive toward isocyanate groups or functional groups inert at temperatures of up to 100° C. 
     
     
         19 . The two-component coating composition of  claim 1 , wherein x in formula (V) is 2 to 4. 
     
     
         20 . The two-component coating composition of  claim 1 , wherein for formula (VI): R3 is hydrogen and R4 is a methyl radical.